1. Field of the Invention
The present invention relates to a box provided with a breakable seal which is broken as the box is opened and, more specificablly, a box of the type including one or more closure covers against which latching teeth projecting from the underlaying flaps of each cover interfere in order to remarkably increase the resistance against opening of the box.
2. Discussion of the Related Art
In the U.S. Pat. No. 4,890,789 patent corresponding to the European EP-B-0318750 patent and moreover in the German Patent Application DE-A-3826231 there are disclosed boxes provided with covers (in general only the bottom cover of each box) having a high resistance against opening. The cover intended for presenting a high resistance against opening is provided with a folded tongue which can be introduced into the inside of the box, laterally of one or more flaps projecting from some main panels of the box and just arranged under the related cover (this construction being a conventional construction for all of the like type boxes). The box is characterized in that through the tongue there is formed a thin elongated window or slit therein engage (with the box being closed) hook or dovetail shape teeth which project from the mentioned tongues.
As a pulling force is exerted on the cover, in order to open it, the mentioned teeth are raised away from their rest positions, since these teeth are rigid with the tongues which in turn are connected to the adjoining main panels of the box along slanted folding lines (in general perpendicular) with respect to the folding line thereabout the cover can turn. The raising movement of the teeth (under the pulling force exerted thereon by the cover to be opened) causes the teeth to spread apart with respect to the window in which they are engaged, so as to strongly engage with the tongue therethrough the window or slit is provided.
Thus, the resistance against opening of the box cover is greatly increased by the restraining force exerted thereon by the teeth projecting from the box flaps.
However, by suitable operations, one can still open the box cover or covers and then reclose them without having trace of a previous opening thereof.